hi, i came across this blog which lists a good mix of things for the families and all have some sort of voucher which you print off from the Visit Heart of England website in their Schools Out e-voucher booklet. I've already used Drayton Manor and ThinkTank vouchers.
visitheartofengland.tumblr.com/post/8089194059/schools-out-campaign-2011-summertime-kids-are#disqus_thread